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Video of reactor 1 at Fukushima plant

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Re: Video of reactor 1 at Fukushima plant

#41

Post by uvdiv »

craigmccaskill wrote: post #31
koski wrote: post #25

what I understand now is that the blast at the nuclear plant may have been caused by a hydrogen explosion (pressure) or If nuclear fuel rods overheat and then come into contact with water, this produces a large amount of highly-flammable hydrogen gas which can then ignite. Right? Can anyone with more knowledge and experience of this confirm?

That's certainly possible, theoretically. However, I'm not sure if those conditions can actually be met (rods should not ever come into contact with water and nothing should be able to ignite the gas, especially not at higher pressure levels).

No, actually the fuel pellets never need to come in contact with water; it is their cladding, which is a zirconium alloy ("Zircaloy"), which can react with steam under extreme conditions. It's a redox reaction: Zr + 2H2O --> ZrO2 + 2H2 or something similar.

This actually happened at Three Mile Island, and there was a hydrogen explosion in the containment building there (which did not break).

(I am not an engineer)

Re: Video of reactor 1 at Fukushima plant

#42

Post by rwmj »

uxp wrote: post #15
csulok wrote: post #10

Earlier quoted context omitted.

it looks to me like a still-standing structure completely disappeared. watch the replay a couple times. there's a white building not unlike 2 other to the right, is partially covering a lightning rod. when you see the shockwave, it's no longer there, at all.

This picture just appeared on Wikipedia, of which I am guessing is the building that may or may not be the one that possibly exploded. Maybe someone more knowledgable than myself can identify what the building is used for. The 2011 Sendai earthquake article says " the outer structure of reactor number 1's containment building had blown off, releasing a large cloud of dust and vapour." http://en.wikipedia.org/wiki/Fil…

Wikipedia deletionists have already put a speedy deletion tag on that. Go Wikipedia!

Re: Video of reactor 1 at Fukushima plant

#43

Post by JanezStupar »

wazoox wrote: post #34
koski wrote: post #22

Earlier quoted context omitted.

"This is starting to look a lot like Chernobyl" Walt Patterson, an associate fellow with Chatham House, has told the BBC after seeing pictures of the explosion at the Fukushima-Daiichi nuclear plant. "The nuclear agency says that they have detected caesium and iodine outside the unit, which certainly indicates fuel melting at the very least," he says. "Once you have melting fuel coming into contact with water, that w…

This is quite different from Chernobyl, which didn't even have a proper confinement wall. It's unlikely that it can get as bad as Chernobyl was.

It seems that proper containment is gone in this case...

Re: Video of reactor 1 at Fukushima plant

#44

Post by craigmccaskill »

uvdiv wrote: post #41
craigmccaskill wrote: post #31

Earlier quoted context omitted.

That's certainly possible, theoretically. However, I'm not sure if those conditions can actually be met (rods should not ever come into contact with water and nothing should be able to ignite the gas, especially not at higher pressure levels).

No, actually the fuel pellets never need to come in contact with water; it is their cladding, which is a zirconium alloy ("Zircaloy"), which can react with steam under extreme conditions. It's a redox reaction: Zr + 2H2O --> ZrO2 + 2H2 or something similar. This actually happened at Three Mile Island, and there was a hydrogen explosion in the containment building there (which did not break). (I am not an engineer)

That makes more sense, thanks.

Re: Video of reactor 1 at Fukushima plant

#45

Post by uvdiv »

ajb wrote: post #39

Any opinions on what the thing rising up very quickly during the explosion is? I initially thought it was the roof, but I'm wondering now if it isn't actually a flame from burning hydrogen. Ideas?

It looks like a hydrogen flame to me. The color is right (faint blue, barely visible), and see how fast it rises straight up?

(I am not an engineer)

Re: Video of reactor 1 at Fukushima plant

#46

Post by btmorex »

koski wrote: post #35
ck2 wrote: post #8

http://news.google.com/news/more?ncl=d_LFixACgsQEvVMNHMag3MA... There is almost guaranteed significant radiation release. quote from slashdot: The outer walls of the Reactor 1 building have partially blown off, leaving only what looks like a steel frame. NHK is saying that a sensor within 5km of the plant is detecting radiation levels approaching 1015 microsieverts - that is apparently a year's worth of radiation exp…

Japanese authorities are extending the evacuation zone around the two Fukushima nuclear plants from 10km to 20km, according to local media.

Well, judging from past nuclear accidents (Chernobyl, 3 mile island), I would:

1.) Not trust the government, the plant operator, the plant designer, hell anyone remotely involved. They always downplay whatever is really going on to prevent panic (or divert blame)

2.) Get as far away as possible, preferably in the opposite direction of prevailing winds.

Re: Video of reactor 1 at Fukushima plant

#48

Post by desigooner »

koski wrote: post #22
ck2 wrote: post #8

http://news.google.com/news/more?ncl=d_LFixACgsQEvVMNHMag3MA... There is almost guaranteed significant radiation release. quote from slashdot: The outer walls of the Reactor 1 building have partially blown off, leaving only what looks like a steel frame. NHK is saying that a sensor within 5km of the plant is detecting radiation levels approaching 1015 microsieverts - that is apparently a year's worth of radiation exp…

"This is starting to look a lot like Chernobyl" Walt Patterson, an associate fellow with Chatham House, has told the BBC after seeing pictures of the explosion at the Fukushima-Daiichi nuclear plant. "The nuclear agency says that they have detected caesium and iodine outside the unit, which certainly indicates fuel melting at the very least," he says. "Once you have melting fuel coming into contact with water, that w…

BBC environment correspondent Roger Harrabin says local officials believe the release of radiation following the nuclear plant explosion is likely to be small. He adds that nuclear incidents aren't always as serious as they may sound or appear, and actually, in terms of loss of life and destruction, accidents at hydroelectric plants are far more dangerous.

Re: Video of reactor 1 at Fukushima plant

#49

Post by nossralf »

uxp wrote: post #15
csulok wrote: post #10

Earlier quoted context omitted.

it looks to me like a still-standing structure completely disappeared. watch the replay a couple times. there's a white building not unlike 2 other to the right, is partially covering a lightning rod. when you see the shockwave, it's no longer there, at all.

This picture just appeared on Wikipedia, of which I am guessing is the building that may or may not be the one that possibly exploded. Maybe someone more knowledgable than myself can identify what the building is used for. The 2011 Sendai earthquake article says " the outer structure of reactor number 1's containment building had blown off, releasing a large cloud of dust and vapour." http://en.wikipedia.org/wiki/Fil…

http://www.ansn-jp.org/jneslibrary/npp2.pdf

That PDF has a schematic of the containment building on page 4. The "MARK-I" image corresponds to the Fukushima I-1 building.

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